Hydroxylated anthranilic acid derivatives

ABSTRACT

The present invention relates to novel derivatives of 3-hydroxyanthranilic acid, 3-HANA, of the general formula I ##STR1## wherein R 1  and R 2  are the same or different and selected from H and alkyl; X and Y are the same or different and selected from alkoxy, aryloxy, alkyl, alkylthio, arylthio, fluoroalkyl, halogen, cyano, OCF 3  and SCF 3  with the proviso that the compound of formula I wherein R 1  and R 2  =H, X=Br and Y=Me is excluded; 
     or a pharmaceutically acceptable salt thereof, methods and intermediates for their preparation, novel pharmaceutical compositions and the use thereof for inhibiting the enzyme 3-hydroxyanthranilate oxygenase, 3-HAO, responsible for the production of the endogenous neurotoxin quinolinic acid, QUIN.

This application is a 371 of PCT/SE94/00153 Feb. 24, 1995.

FIELD OF INVENTION

The present invention relates to novel derivatives of3-hydroxyanthranilic acid, 3-HANA, methods and intermediates for theirpreparation, novel pharmaceutical compositions and the use thereof forinhibiting the enzyme 3-hydroxyanthranilate oxygenase, 3-HAO,responsible for the production of the endogenous neurotoxin quinolinicacid, QUIN.

BACKGROUND OF THE INVENTION

3-HAO is the enzyme in the catabolic pathway of tryptophan responsiblefor the conversion of 3-hydroxyanthranilic acid into quinolinic acid.Both QUIN and its biosynthetic enzyme 3-HAO have been identified inrodent as well as in human brain tissue. QUIN is an excitatoryamino-acid acting through the N-methyl-D-aspartate (NMDA) receptor andhas recently gained attention for its putative role as an endogenuosexcitotoxin involved in neurodegenerative disorders such as Huntington'sdisease, stroke/cerebral ischemia, hypoxia, Alzheimers disease and theAids dementia complex as well as epilepsi. Inhibitors of 3-HAO activityare of obvious therapeutic interest in diseases which can be traced toan overabundance of quinolinic acid.

PRIOR ART

4-Halogenated substrate analogs have been described as inhibitors of3-HAO activity. In 1980 it was shown by Parli C J, Krieter P, Schmedt B,in "Metabolism of 6-chlorotryptophan to 4-chloroanthranilic acid: Apotent inhibitor of 3-hydroxyanthranilic acid oxidase", Arch Biochem andBiophys 203, pp 161-166, 1980, that 4-chloro-3-hydroxyanthranilic acid,a metabolite of 6-chlorotryptophan, is a potent inhibitor of 3-HAO inrat and pig liver and kidney. Later it was verified by Heyes M P, HuttoB, Markey S P, in "4-Chloro-3-hydroxyanthranilate inhibits brain3-hydroxyanthranilate oxidase", Neurochem Int 13, pp 405-408, 1988, that4-chloro-3-hydroxyanthranilic acid also is an inhibitor of rat brain3-HAO. In 1989 Todd W P, Carpenter B K and Schwarcz R, in "Preparationof 4-halo-3-hydroxyanthranilates and demonstration of their inhibitionof 3-hydroxyanthranilate oxygenase activity in rat and human braintissue," Prep Biochem 19, pp 155-165, 1989, showed that 4-fluoro-,4-chloro- and 4-bromo-3-hydroxyanthranilic acid had very similarblocking potencies of 3-HAO in rat as well as in human brain.

BRIEF DESCRIPTION OF INVENTION

The present invention relates to compounds able to inhibit the enzyme3-HAO with IC₅₀ values similar to and in addition a stability superiorto compounds according to the prior art.

The present invention, thus is related to a compound of the generalformula I ##STR2## wherein R¹ and R² are the same or different andselected from H, alkyl, aryl and arylalkyl; X and Y are the same ordifferent and selected from alkoxy, aryloxy, alkyl, alkylthio, arylthio,fluoroalkyl, halogen, cyano, OSO₂ CH₃, OSO₂ CF₃, OCF₃ and SCF₃ with theproviso that the compound of formula I wherein R¹ and R² =H, X=Br andY=Me is excluded; or a pharmaceutically acceptable salt thereof.

Another object of the invention is a process for the preparation of thecompound of formula I by

A) in the case where R¹ and R² =H; X and Y are the same or different andselected from alkoxy, aryloxy, alkyl, alkylthio, arylthio, fluoroalkyl,halogen, cyano, OSO₂ CH₃, OSO₂ CF₃, OCF₃ and SCF₃

reducing a compound of formula II ##STR3## wherein X and Y are asdefined in A) above; B) in the case where R¹ and R² are the same ordifferent and selected from H, alkyl, aryl and arylalkyl; X and Y arethe same or different and selected from alkoxy, aryloxy, alkyl,alkylthio, arylthio, fluoroalkyl, halogen, cyano, OSO₂ CH₃, OSO₂ CF₃,OCF₃ and SCF₃

deprotecting a compound of formula III ##STR4## wherein R¹, R², X and Yare as defined in B) above and PG is a protecting group such as alkyl,benzyl (Bn), 2-(trimethylsilyl)ethoxymethyl (SEM), methoxymethyl (MOM)or 2-methoxyethoxymethyl (MEM);

C) in the case where R¹ and R² are the same or different and selectedfrom H, alkyl, aryl and arylalkyl; X and Y are the same or different andselected from alkoxy, aryloxy, alkyl, alkylthio, arylthio, fluoroalkyl,halogen, cyano, OSO₂ CH₃, OSO₂ CF₃, OCF₃ and SCF₃

deesterifying a compound of formula IV ##STR5## wherein R¹, R², X and Yare as defined in C) above and R³ is selected from alkyl, Bn, SEM, MEM,MOM and 2,2,2-trichloroethyl;

D) in the case where R¹ and R² are the same or different and selectedfrom H, alkyl, aryl and arylalkyl; X and Y are the same or different andselected from alkoxy, aryloxy, alkyl, alkylthio, arylthio, fluoroalkyl,halogen, cyano, OSO₂ CH₃ , OSO₂ CF₃, OCF₃ and SCF₃

deesterifying and deprotecting a compound of formula V ##STR6## whereinR¹, R², X and Y are as defined in D) above nd R³ and PG are selectedfrom alkyl, Bn, SEM, MEM and MOM; or

E) in the case where R¹ =alkyl, aryl or arylalkyl R² =H, alkyl, aryl orarylalkyl; X and Y are the same or different and selected from alkoxy,aryloxy, alkyl, alkylthio, arylthio, fluoroalkyl, halogen, cyano, OSO₂CH₃, OSO₂ CF₃, OCF₃ and SCF₃

alkylating a compound of formula VI ##STR7## wherein X and Y are asdefined in E) above.

The present invention is also related to a pharmaceutical formulationcontaining a compound of formula I as active ingredient and apharmaceutically acceptable carrier, the use of said compound for themanufacture of a medicament for the prevention or treatment ofneurodegeneration.

Further objects of the invention are synthesis intermediates for thepreparation of compounds of formula I, namely a compound of the generalformula II ##STR8## wherein X and Y are the same or different andselected from alkoxy, aryloxy, alkyl, alkylthio, arylthio, fluoroalkyl,halogen, cyano, OSO₂ CH₃, OSO₂ CF₃, OCF₃ and SCF₃ with the proviso thatcompounds of formula II wherein X and Y=iodide; X=Br and Y=CH₃ areexcluded;

a compound of the general formula III ##STR9## wherein R¹ and R² are thesame or different and selected from H, alkyl, aryl and arylalkyl; X andY are the same or different and selected from alkoxy, aryloxy, alkyl,alkylthio, arylthio, fluoroalkyl, halogen, cyano, OSO₂ CH₃, OSO₂ CF₃,OCF₃ and SCF₃ and PG is a protecting group such as alkyl, Bn, SEM, MEMor MOM with the proviso that compounds of formula III where in R¹ and R²=H, X=OCH₃, Y=Br, Cl or OCH₃ and PG=CH₃ are excluded;

a compound of the general formula IV ##STR10## wherein R¹ and R² are thesame or different and selected from H, alkyl, aryl and arylalkyl; X andY are the same or different and selected from alkoxy, aryloxy, alkyl,alkylthio, arylthio, fluoroalkyl, halogen, cyano, OSO₂ CH₃, OSO₂ CF₃,OCF₃ and SCF₃ ; and R³ is selected from alkyl, Bn, SEM, MEM, MOM and2,2,2-trichloroethyl;

a compound of the general formula V ##STR11## wherein R¹ and R² are thesame or different and selected from H, alkyl, aryl and arylalkyl; X andY are the same or different and selected from alkoxy, aryloxy, alkyl,alkylthio, arylchio, fluoroalkyl, halogen, cyano, OSO₂ CH₃, OSO₂ CF₃,OCF₃ and SCF₃ ; R³ and PG are selected from alkyl, Bn, SEM, MEM and MOMwith the proviso that compound of formula V wherein R¹ and R² =H,X=OCH₃, Y=Cl, PG and R³ =CH₃ is excluded; and

a compound of the general formula VI ##STR12## wherein X and Y are thesame or different and selected from alkoxy, aryloxy, alkyl, alkylthio,arylthio, fluoroalkyl, halogen, cyano, OSO₂ CH₃, OSO₂ CF₃, OCF₃ and SCF₃with the proviso that compound of formula VI wherein X=Br and Y=CH₃ isexcluded.

DETAILED DESCRIPTION OF THE INVENTION

The following definitions shall apply throughout the specification andthe appended claims.

Unless otherwise stated or indicated, the term "alkyl" denotes astraight or branched lower alkyl group, preferably a C₁ -C₆ alkyl.Examples of said lower alkyl include methyl, ethyl, n-propyl,iso-propyl, n-butyl, iso-butyl, sec-butyl, t-butyl and straight- andbranched-chain pentyl and hexyl.

Unless otherwise stated or indicated, the term "aryl" denotes a phenyl,naphthyl, furyl, thienyl, pyridyl or pyrrolyl group, itself optionallysubstituted.

Unless otherwise stated or indicated, the term "aryl-alkyl" denotes alower alkyl group as defined above substituted by an aryl group asdefined above. Examples of said arylalkyl include benzyl, phenethyl,phenylpropyl, phenylbutyl, 2,4-dimethoxyphenylmethyl, furfuryl,3-furylmethyl, tolylethyl and thenyl.

Unless otherwise stated or indicated, the term "alkoxyl" denotes astraight or branched lower alkoxy group, preferably a C₁ -C₆ alkoxy.Examples of said lower alkoxy include methoxy, ethoxy, n-propoxy,iso-propoxy, n-butoxy, iso-butoxy, sec-butoxy, t-butoxy and straight-and branched-chain pentoxy and hexoxy.

Unless otherwise stated or indicated, the term "alkylthio" denotes astraight or branched lower alkylthio preferably a C₁ -C₆ alkylthio.Examples of said lower alkylthio include methylthio, ethylthio,n-propylthio, iso-propylthio, n-butylthio, iso-butylthio, sec-butylthio,t-butylthio and straight- and branched-chain pentylthio and hexylthio.

Unless otherwise stated or indicated, the term "aryuthino" denotes aphenylthio group in which the phenyl ring is optionally furthersubstituted by lower alkyl lower alkoxy or halogen.

Unless otherwise stated or indicated, the term "aryloxy" denotes aphenoxy group in which the phenyl ring is optionally further substitutedby lower alkyl, lower alkoxy or halogen.

Unless otherwise stated or indicated, the term "halogen" shall meanfluorine, chlorine, bromine or iodine.

The best mode o f carrying out the invention known at present is to use4,6-dibromo-3-hydroxyanthranilic acid or4,6-dichloro-3-hydroxyanthranilic acid.

The compounds according to the present invention may be used inconnection with prevention or treatment of neurodegeneration, especiallyin connection with conditions such as stroke, cerebral ischaemia,hypoxia, epilepsy and in neurodegenerative diseases such as Alzheimer'sdisease, multi-infarct dementia, Huntington's disease and the AIDSdementia complex.

Below the methods for the preparation of the compound of formula I willbe described in detail.

Methods of Preparation

The compound of formula I ##STR13## wherein R¹ and R² are the same ordifferent and selected from H, alkyl, aryl and arylalkyl; X and Y arethe same or different and selected from alkoxy, aryloxy, alkyl,alkylthio, arylthio, fluoroalkyl, halogen, cyano, OSO₂ CH₃, OSO₂ CF₃,OCF₃ and SCF₃ may be prepared by one of the following methods.

Method A The compound of formula I wherein R¹ and R² are H; X and Y arethe same or different and selected from alkoxy, aryloxy, alkyl,alkylthio, arylthio, fluoroalkyl, halogen, cyano, OSO₂ CH₃, OSO₂ CF₃,OCF₃ and SCF₃ ; may be prepared from compounds of formula II ##STR14##wherein X and Y are as defined in formula I in method A, by reductionwith for example H₂ and a catalyst such as Pd/C, Raney nickel or PtS₂ atatmospheric or elevated pressure in a suitable solvent such as EtOH orEtOAc. The reduction can also be accomplished by reaction with SnCl₂,NH₂ NH₂.H₂ O or Na₂ S₂ O₅ in a suitable solvent such as EtOH.

Method B The compounds of the general formula I wherein R¹ and R² arethe same or different and selected from H, alkyl, aryl and arylalkyl; Xand Y are the same or different and selected from alkoxy, aryloxy,alkyl, alkylthio, arylthio, fluoroalkyl, halogen, cyano, OSO₂ CH₃, OSO₂CF₃, OCF₃ and SCF₃ ; may be prepared from compounds of the generalformula III ##STR15## wherein R¹, R², X and Y are as defined in formulaI in method B and PG is selected from alkyl, Bn, SAM, MEM and MOM, bydeprotection with for example a Lewis acid such as BBr₃ ortrimethylsilyl iodide or with alkyl- or arylSNa or alkyl- or arylSLifollowed by adjustment of the pH to obtain the 3-hydroxyanthranilic acidderivative. In the case where PG=SEM, deprotection can be performedusing tetrabutylammonium fluoride (TBAF) or CsF in a suitable solventsuch as N,N-dimethylpropylenurea (DMPU) or N,N-dimethylformamide (DMF)at elevated temperature. A benzyl group can be removed by hydrogenolysisusing for example H₂ and Pd/C or PtS₂ as a catalyst. A2,2,2-trichloroethyl group can be removed using Zn in acetic acid.

Method C The compounds of formula I wherein R¹ and R² are the same ordifferent and selected from H, alkyl, aryl and arylalkyl; X and Y arethe same or different and selected from alkoxy, aryloxy, alkyl,alkylthio, arylthio, fluoroalkyl, halogen, cyano, OSO₂ CH₃, OSO₂ CF₃,OCF₃ and SCF₃ ; may be prepared from compounds of formula IV ##STR16##wherein R¹, R², X and Y are as defined in formula I in method C and R³is selected from alkyl, Bn, SEM, MEM, MOM and 2,2,2-trichloroethyl, bydeesterifying with for example a base such as KOH in a suitable solventsuch as MeOH at room temperature or at elevated temperature, or byalkyl- or arylSLi or alkyl- or arylSNa or with Me₃ SiI followed byadjustment of the pH to obtain the 3-hydroxyanthranilic acid deivative.In the case where R³ =Bn the carboxylic acid can be obtained byhydrogenolysis with for example H₂ and Pd/C or PtS₂. A2,2,2-trichloroethylester can be cleaved for example with Zn in HOAc anda SEM-ester for example with TBAF in DMPU.

Method D The compounds of formula I wherein R¹ and R² are the same ordifferent and selected from H, alkyl, aryl and arylalkyl; X and Y arethe same or different and selected from alkoxy, aryloxy, alkyl,alkylthio, arylthio, fluoroalkyl, halogen, cyano, OSO₂ CH₃, OSO₂ CF₃,OCF₃ and SCF₃ ; may be prepared from compounds of formula V ##STR17##wherein R¹, R², X and Y are as defined in formula I in method D; PG andR³ are selected from alkyl, Bn, SEM, MEM and MOM, by deesterificationand deprotection with for example alkyl- or arylSLi, alkyl- or arylSNaor with Me₃ SiI followed by adjustment of the pH to obtain the3-hydroxyanthranilic acid derivative. In the case where PG and R³ =Bnthe 3-hydroxyanthranilic acid derivative can be obtained byhydrogenolysis for example with H₂ and Pd/C or PtS₂ and if PG and R³=SEM, TBAF can be used.

Method E The compound of formula I wherein R¹ =alkyl, aryl or arylalkyl;R² =H, alkyl, aryl or arylalkyl; X and Y are the same or different andselected from alkoxy, aryloxy, alkyl, alkylthio, arylthio, fluoroalkyl,halogen, cyano, OSO₂ CH₃, OSO₂ CF₃, OCF₃ and SCF₃ ; may be prepared fromcompounds of formula VI ##STR18## wherein X and Y are as defined informula I in method E, by reductive alkylation with for example analdehyde corresponding to R¹ and a reducing agent such as NaCNBH₃ andHCl in a suitable solvent such as CH₃ CN, H₂ O or MeOH. Mono- anddi-N-alkylated derivatives can be separated for example bychromatography.

Intermediates

Method II:a Compounds of formula II wherein X and Y are the same ordifferent and selected from alkoxy, alkyl, alkylthio, fluoroalkyl,halogen, cyano, OSO₂ CH₃, OSO₂ CF₃, OCF₃ and SCF₃ ; may be prepared fromcompounds of formula VII ##STR19## wherein X and Y are as defined informula II in method II:a, by nitration using for example HNO₃ in asolvent such as CH₃ NO₂, CH₂ Cl₂ or H₂ O or a mixture of HNO₃ and H₂SO₄.

Method II:b Compounds of formula II wherein X and Y are the same ordifferent and selected from alkoxy, aryloxy, alkyl, alkylthio, arylthio,fluoroalkyl, halogen, cyano, OSO₂ CH₃, OSO₂ CF₃, OCF₃ and SCF₃ ; may beprepared from compounds of formula VIII ##STR20## wherein X and Y are asdefined in formula II in method II:b and PG is selected from alkyl, Bn,SEM, MEM and MOM, by deprotection for example according to method B.

Method II:c Compounds of formula II wherein X=Br, Cl or I; Y is selectedfrom alkoxy, alkyl, alkylthio, fluoroalkyl, halogen, cyano, OSO₂ CH₃,OSO₂ CF₃, OCF₃ and SCF₃ ; may be prepared from compounds of formula IX##STR21## wherein Y is as defined in formula II in method II:c, byhalogenation with for example Br₂ or Cl₂ in acetic acid at room- orelevated temperature. Alternatively, IX could be halogenated with Br₂ orI₂ and mercuric trifluoroacetate in trifluoroacetic acid at room- orelevated temperature.

Method II:d Compounds of formula II wherein X is selected from alkoxy,alkyl, alkylthio, fluoroalkyl, halogen, cyano, OSO₂ CH₃, OSO₂ CF₃, OCF₃and SCF₃ ; Y=Br, Cl or I; may be prepared from compounds of formula X##STR22## wherein X is as defined in formula II in method II:d, byhalogenation for example according to method II:c.

Method II:e Compounds of formula II wherin X and Y are the same ordifferent and selected from alkoxy, aryloxy, alkyl, alkylthio, arylthio,fluoroalkyl, halogen, cyano, OSO₂ CH₃, OSO₂ CF₃, OCF₃ and SCF3; may beprepared from compounds of formula XI ##STR23## wherein X and Y are asdefined in formula II in method II:e and R³ =alkyl, Bn, SEM, MEM, MOM or2,2,2-trichloroethyl, by deesterification for example according tomethod C.

Method II:f Compounds of formula II wherein X and Y=Br, Cl or I may beprepared from compounds of formula XX ##STR24## by halogenationaccording to method II:c. Method III:a Compounds of formula III whereinand R² =H; X and Y are the same or different and selected from alkoxy,aryloxy, alkyl, alkylthio, arylthio, fluoroalkyl, halogen, cyano, OSO₂CH₃, OSO₂ CF₃, OCF₃ and SCF₃ and PG is selected from alkyl, Bn, SEM, MEMand MOM; may be prepared from compounds of formula VIII ##STR25##wherein X, Y and PG are as defined in formula III in method III:a, byreduction for example according to method A.

Method III:b Compounds of formula III wherein R¹ and R² =H; X and Y arethe same or different and selected from alkoxy, alkyl, alkylthio,fluoroalkyl, chloro, fluoro and OCF₃ ; PG is selected from alkyl, SEMand MOM; may be prepared from compounds of formula XII ##STR26## whereinX, Y and PG are as defined in formula III in method III:b; DMG isselected from COtBu, CO₂ tBu and COCF₃ ; Z=H or Br by reaction with forexample alkyllithium in a suitable solvent such as tetrahydrofuran(THF)at low temperature. The aryllithium derivative is then reacted with CO₂(s), acidified and the DMG group is removed by aqueous HCl at elevatedtemperature.

Method III:c Compounds of formula III wherein R¹ =H, alkyl, aryl orarylalkyl; R² =H; X and Y are the same or different and selected fromalkoxy, aryloxy, alkyl, fluoroalkyl, halogen and OSO₂ CH₃, OSO₂ CF₃,OCF₃ ; PG is selected from alkyl, Bn, MEM and MOM; may be prepared fromcompounds of formula XIII ##STR27## wherein X, Y, R¹ and PG are asdefined in formula III in method III:c, by reacting a compound offormula XIII with for example H₂ O₂ and NaOH in a suitable solvent suchas water or dioxan. The pH is then adjusted to obtain the anthranilicacid derivative.

Method III:d Compounds of formula III wherein R¹ and R² are the same ordifferent and selected from H, alkyl, aryl and arylalkyl; X and Y arethe same or different and selected from alkoxy, aryloxy, alkyl,alkylthio, arylthio, fluoroalkyl, halogen, cyano, OSO₂ CH₃, OSO₂ CF₃,OCF₃ and SCF₃ ; PG is selected from alkyl, Bn, SEM, MEM and MOM; may beprepared from compounds of formula V ##STR28## wherein R¹ R² X, Y and PGare as defined in formula III in method III:d and R³ is selected fromalkyl, Bn, SEM, MEM, MOM and 2,2,2-trichloroethyl and different from PG,by deesterification for example according to method C.

Method III:e Compounds of formula III wherein R¹ and R² are the same ordifferent and selected from H, alkyl, aryl and arylalkyl; X and Y arethe same or different and selected from alkoxy, aryloxy, alkyl,alkylthio, arylthio, fluoroalkyl, fluoro, chloro, cyano, OSO₂ CH₃, OCF₃and SCF₃ and PG is selected from alkyl and Bn; may be prepared fromcompounds of formula XVIII ##STR29## wherein R¹, R², X, Y and PG are asdefined in formula III in method III:e and Z=OSO₂ CF₃, I or Br, byreacting a compound of formula XVIII with for example a mixture ofPd(OAc)₂, CO, 1,3-bis(diphenylphosphino)-propane and water in a suitablesolvent such as DMF or dioxan containing a base such as Et₃ N.

Method IV:a Compounds of formula IV wherein R¹ and R² =H; X and Y arethe same or different and selected from alkoxy, aryloxy, alkyl,alkylthio, arylthio, fluoroalkyl, halogen, cyano, OSO₂ CH₃, OSO₂ CF₃,OCF₃ and SCF₃ ; R³ is selected from alkyl, Bn, SEM, MEM, MOM and2,2,2-trichloroethyl; may be prepared from compounds of formula XI##STR30## wherein X, Y and R³ are as defined in formula IV in methodIV:a, by reduction for example according to method A.

Method IV:b Compounds of formula IV wherein R¹ and R² are the same ordifferent and selected from H, alkyl, aryl and arylalkyl; X and Y arethe same or different and selected from alkoxy, aryloxy, alkyl,alkylthio, arylthio, fluoroalkyl, halogen, cyano, OSO₂ CH₃, OSO₂ CF₃,OCF₃ and SCF₃ ; and R³ is selected from akyl, Bn, SEM, MEM, MOM and2,2,2-trichloroethyl; may be prepared from compounds of formula V##STR31## wherein R¹, R², X, Y and R³ are as defined in formula IV inmethod IV:b and PG is selected from alky.l, Bn, SEM, MEM and MOM anddifferent from R³, by deprotection for example according to method B.

Method IV:c Compounds of formula IV wherein R¹ =H, alkyl, aryl orarylalkyl; R² =alkyl, aryl or arylalkyl; X and Y are the same ordifferent and selected from alkoxy, aryloxy, alkyl, alkylthio, arylthio,fluoroalkyl, halogen, cyano, OSO₂ CH₃, OSO₂ CF₃, OCF₃ and SCF₃ ; R³ isselected from alkyl, benzyl, SEM, MEM, MOM and 2,2,2-trichloroethyl; maybe prepared from compounds of formula XIV ##STR32## wherein X, Y and R³are as defined in formula IV in method IV:c, by alkylation for exampleaccording to method E.

Method V:a Compounds of formula V wherein R¹ and R² =H; X and Y are thesame or different and selected from alkoxy, aryloxy, alkyl, alkylthio,arylthio, fluoroalkyl, halogen, cyano, OSO₂ CH₃, OSO₂ CF₃, OCF₃ and SCF₃; R³ and PG are selected from alkyl, Bn, SEM, MEM and MOM; may beprepared from compounds of formula XV ##STR33## wherein X, Y, R³ and PGare as defined in formula V in method V:a, by reduction for exampleaccording to method A.

Method V:b Compounds of formula V wherein R¹ and R² =H; X and Y are thesame or different and selected from alkoxy, aryloxy, alkyl, alkylthio,arylthio, fluoroalkyl, halogen, cyano, OCF₃ and SCF₃ ; R³ and PG areselected from alkyl, Bn and SEM; may be prepared from compounds offormula XVI ##STR34## wherein X, Y, R³ and PG are as defined in formulaV in method V:b and R⁴ =t-Bu, t-BuO or CF₃, by hydrolysis with forexample an acid such as HCl(aq) or CF₃ COOH followed by adjustment ofthe pH to obtain the anthranilic acid derivative.

Method V:c Compounds of formula V wherein R¹ =H, alkyl, aryl orarylalkyl; R² =alkyl, aryl or arylalkyl; X and Y are the same ordifferent and selected from alkoxy, aryloxy, alkyl, alkylthio, arylthio,fluoroalkyl, halogen, cyano, OSO₂ CH₃, OSO₂ CF₃, OCF₃ and SCF₃ ; R³ andPG are selected from alkyl, Bn, SEM, MEM and MOM; may be prepared fromcompounds of formula XVII ##STR35## wherein X, Y, R³ and PG are asdefined in formula V in method V:c, by alkylation for example accordingto method E.

Method V:d Compounds of formula V wherein R¹ and R² are the same ordifferent and selected from H, alkyl, aryl and arylalkyl; X and Y arethe same or different and selected from alkoxy, aryloxy, alkyl,alkylthio, arylthio, fluoroalkyl, fluoro, chloro, cyano, OSO₂ CH₃, OCF₃and SCF₃ ; R³ and PG are selected from alkyl and Bn; may be preparedfrom compounds of formula XVIII ##STR36## wherein R¹, R₂, X, Y and PGare as defined in formula V in method V:d and Z=OSO₂ CF₃, I or Br, byreacting a compound of formula XVIII with for example a mixture ofPd(OAc)₂, CO, 1,3-bis(diphenylphosphino)-propane and an alcoholcorresponding to R₃ in a suitable solvent such as DMF or dioxancontaining a base such as Et₃ N.

Method V:e Compounds of formula V wherein R¹ and R² =H; X and Y are thesame or different and selected from alkoxy, alkyl, alkylthio,fluoroalkyl, chloro, fluoro and OCF₃ ; PG is selected from alkyl, SEMand MOM; may be prepared from compounds of formula XII ##STR37## whereinX, Y and PG are as defined in formula V in method V:e; DMG=COtBu, CO₂tBu or COCF₃ ; Z=H or Br, by reaction with for example alkyllithium in asuitable solvent such as THF at low temperature. The aryllithiumderivative is then reacted with methyl or benzyl chloroformiate and theDMG group is removed by aqueous HCl at elevated temperature.

Method VI:a Compounds of formula VI wherein X and Y are the same ordifferent and selected from alkoxy, aryloxy, alkyl, alkylthio, arylthio,fluoroalkyl, halogen, cyano, OSO₂ CH₃, OSO₂ CF₃, OCF₃ and SCF₃ ; may beprepared from compounds of formula II ##STR38## wherein X and Y are thesame as defined in formula VI in method VI:a, by reduction for exampleaccording to method A.

Method VI:b Compounds of formula VI Wherein X and Y are the same ordifferent and selected from alkoxy, aryloxy, alkyl, alkylthio, arylthio,fluoroalkyl, halogen, cyano, OSO₂ CH₃, OSO₂ CF₃, OCF₃ and SCF₃ ; may beprepared from compounds of formula XIX ##STR39## wherein X and Y are asdefined in formula VI in method VI:b and PG is selected from alkyl, Bn,SEM, MEM and MOM, by deprotection for example according to method B.

Method VI:c Compounds of formula VI wherein X and Y are the same ordifferent and selected from alkoxy, aryloxy, alkyl, alkylthio, arylthio,fluoroalkyl, halogen, cyano, OSO₂ CH₃, OSO₂ CF₃, OCF₃ and SCF₃ ; may beprepared from compounds of formula XIV ##STR40## wherein X and Y are asdefined in formula VI in method VI:c and R³ is selected from alkyl, Bn,SEM, MEM, MOM and 2,2,2-trichloroethyl, by deesterifying for exampleaccording to method C.

Method VI:d Compounds of formula VI wherein X and Y are the same ordifferent and selected from alkoxy, aryloxy, alkyl, alkylthio, arylthio,fluoroalkyl, halogen, cyano, OSO₂ CH₃, OSO₂ CF₃, OCF₃ and SCF₃ ; may beprepared from compounds of formula XVII ##STR41## wherein X and Y are asdefined in formula VI in method VI:d and R³ and PG are selected fromalkyl, Bn, SEM, MEM and MOM, by deesterification and deprotection forexample according to method D.

WORKING EXAMPLES Example 1 (Method A) Preparation of4,6-dibromo-3-hydroxyanthranilic acid

4,6-Dibromo-3-hydroxy-2-nitrobenzoic acid

To a cooled, stirred mixture of 3-hydroxy-2-nitrobenzoic acid (10.47 g,0.57 mol) and sodium acetate (9.85 g, 0.57 mol) in HOAc (100 mL), Br₂(6.15 mL, 0.12 mol) was added dropwise. The mixture was stirred at 60°C. for 68 h and then cooled to room temperature and the salts werefiltered off. Evaporation of the filtrate gave a residue which wasdissolved in EtOAc/H₂ O and acidified with HCl (2M). The aqueous phasewas extracted with EtOAc and the combined organic layers dried (MgSO₄)and evaporated to give a crude product (18.9 g). Purification by flashchromatography (SiO₂, toluene--HOAc) followed by crystallization fromMeOH gave the title compound (15.37 g). Mp: 201°-202° C. (dec.). ¹ H NMR(DMSO-d₆): δ 8.20 (s, 1 H). ¹³ C NMR (DMSO-d₆): δ 164.42, 146.93,139.10, 130.48, 116.17, 108.14. MS (EI, 70 eV): m/z (rel. int) 339, 341,343 (M⁺, 49, 98, 46).

4,6-Dibromo-3-hydroxyanthranilic acid

4,6-Dibromo-3-hydroxy-2-nitrobenzoic acid (4.09 g, 12 mmol) and PtS₂(160 mg, 0.62 mmol) in EtOH (150 mL) was hydrogenated at atmosphericpressure and room temperature for 45 h. Filtration and evaporation ofthe filtrate gave a crude product (3.69 g) which was purified by flashchromatography (SiO₂, toluene-EtOAc). Treatment with activated charcoalin MeOH and crystallization from MeOH/H₂ O gave the title compound (2.51g). Mp: 162°-164.5° C. ¹ H NMP (DMSO-d₆): δ 6.96 (s, 1 H). ¹³ C NMR(DMSO-d₆): δ 167.69, 140.56, 139.95, 121.81, 117.23, 112.53, 110.45.MS(EI, 70ev): m/z (rel. int.) 309, 311, 313 (M⁺, 36, 72, 34).

Example 2 (Method A) Preparation of4-bromo-3-hydroxy-6-methoxyanthranilic acid

4-Bromo-3-hydroxy-6-methoxybenzoic acid

3-Hydroxy-6-mezhoxybenzoic acid¹ (1.24 g, 7.40 mmol) was dissolved inacetic acid (100 mL) by heating to 60° C. After cooling to roomtemperature bromine (0.38 mL, 7.4 mmol) was added dropwise. The reactionmixture was stirred for 3 h and then evaporated under reduced pressuregiving a crude product of 1.74 g. Purification by silica gelchromatography (HOAc-toluene 1:10) gave 1.5 g of the title compound. ¹ HNMR (CD₃ OD): δ 7.38 (s, 1 H), 7.26 (s, 1 H), 3.84 (s, 3 H). ¹³ C NMR(CD₃ OD): 67 168.95, 154.07, 149.60, 121.31, 119.63, 119.02, 116.57,57.68.

4-Bromo-3-hydroxy-6-methoxy-2-nitrobenzoic acid

Sodium nitrate (361 mg, 4.25 mmol) was dissolved in water (4 mL) andLaNO₃ *6H₂ O (18 mg, 0.04 mmol) and HCl (12M, 4 mL) were added. Thesolution was cooled to 0° C. and a slurry of4-bromo-3-hydroxy-6-methoxybenzoic acid in diethyl ether (20 mL) wasadded to the reaction mixture in portions during 10 min. After slowlyraising the temperature to room temperature the mixture was stirred for7 h. Extraction between H₂ O (20 ml) and CH₂ Cl₂ (3×30 mL), drying theorganic phase with MgSO4, filtration and evaporation under reducedpressure gave a mixture of products. Purification by silica gelchromatography (HOAc-EtOAc-toluene 1:2:8) gave the title compound (0.6g). ¹ H NMR (CD₃ OD): δ 7.57 (s, 1 H), 3.85 (s, 3 H). MS (EI, 70 eV):m/z (rel.int.) 291/293 (M⁺, 21/19).

4-Bromo-3-hydroxy-6-methoxyantranilic acid

4-Bromo-3-hydroxy-6-methoxy-2-nitrobenzoic acid (52 mg, 0.18 mmol) wasdissolved in EtOH (7 mL) and PtS₂ (2 mg) was added. Hydrogenation atatmospheric pressure and room temperature for 18 h, filtration and thenevaporation under reduced pressure gave 50 mg crude product.Purification on a silica gel column (HOAc-EtOAc-toluene, 1:2:8) gave 30mg of the title compound (95% pure according to HPLC). ¹ H NMR (CD₃ OD):δ 6.40 (s, 1), 3.88 (s, 3 H). ¹³ C NMR (CD₃ OD): δ 170.82, 154.76,145.58, 137.80, 115.54, 102.08, 101.61, 57.62. MS (EI, 70 eV): m/z261/263 (M⁺, 80/79).

Example 3 (Method A) Preparation of6-fluoro-3-hydroxy-4-propylanthranilic acid hydrochloride

Allyl 5-(1,1 -dimethylethyl)dimethylsilyloxy!-2-fluorophenyl! ether

5- (1,1-Dimethylethyl)dimethylsilyloxy!-2-fluorophenol² (65 g, 0.27 mol)was reacted with allyl bromide (40 mL, 0.46 mol) and K₂ CO₃ (50 g,0.36mol) in acetone (200 mL) at reflux temperature for 6 h. Evaporation ofthe solvent, partition of the residue between water (500 mL) and diethylether (500 mL), extraction of the aqueous phase with diethyl ether (250mL) and drying the combined organic phases (MgSO₄) followed byevaporation gave allyl5-(1,1-dimethylethyl)dimethylsilyloxy!-fluoro-phenyl! ether (75 g) as acrude product. A sample was purified by column chromatography (SiO₂)using EtOAc-hexane 5:95 as eluent. ¹ H NMR (CDCl₃): δ 6.91 (dd, J₁ =8.8and J₂ =11.1 Hz, 1 H), 6.46 (dd, J₁ =2.8 and J₂ =7.2 Hz, 1 H), 6.37-6.32(m, 1 H), 6.12-5.89 (m, 1 H), 5.42 (dm, J=17.1 Hz, 1 H), 5.30 (dm,J=10.5 HZ, 1 H), 4.56 (dt, J₁ =1.6 and J₂ =3.7 Hz, 2 H), 0.98 (s, 9 H),0.18 (s, 6 H). MS (EI, 70 eV): m/z (rel.int.) 282 (M⁺, 7).

Allyl (2-fluoro-5-methoxy-phenyl)ether

Allyl 5-(1,1-dimethylethyl)dimethylsilyloxy!-2-fluorophenyl! ether(70 g,70%, 0.17 mol), KF (28.8 g, 0.50 mol) and CH₃ I (52.5 g, 0.37 mol ) werereacted in DMF (300 mL) at room temperature for 1 h 15 min. Potassiumcarbonate (27.6 g, 0.20 mol) was added and the mixture was stirredovernight at room temperature, followed by 4 h at 60° C. Evaporation ofthe solvent gave a residue which was extracted between water and etherand the organic phase was washed with brine, dried (MgSO₄) andevaporated to give allyl (2 -fluoro-5-methoxyphenyl)ether (42.4 g) as acrude product. A sample was purified by column chromatography (SiO₂)using EtOAc-Hexane 1:9 as eluent. ¹ H NMR (CDCl₃): δ 6.98 (dd, J₁ =8.8and J₂ =11.0 Hz, 1 H), 6.53 (dd, J₁ =2.9 and J₂ =7.1 Hz, 1 H), 6.38 (dtJ₁ =3.0 and J₂ =9.0 Hz, 1 H), 6.16-5.95 (m,1 H), 5.42 (dm, J=17.1 Hz, 1H), 5.31 (dm, J=10.4 Hz, 1 H), 4.58 (dt, J₁ =1.5 and J₂ =5.4 Hz, 2 H),3.76 (s, 3 H). MS (EI,70 eV): m/z (rel.int.) 182 (M⁺, 84).

4-Allyl-2-fluoro-5-methoxyphenol

Allyl (2-fluoro-5-methoxyphenyl)ether (32.4 g, 60%, 0.11 mol) wasdissolved in ethylene glycol (150 mL) and heated to 160° C. for 16 h.Water (1 L) and 2M HCl (100 mL) were added followed by extraction withether (500+2×250 mL). The combined organic phases were extracted with0.7M NaOH (500+250 mL). The aqueous phase was acidified with 2M HCl (350ml) and extracted with ether (3×250 ml) and the organic phase was washedwith brine (100 ml), dried (MgSO₄) and concentrated giving 24.5 g ofcrude product. Purification by column chromatography (SiO₂) usingEtOAc-hexane 1:9 as eluent, gave 4-allyl-2-fluoro-5-methoxyphenol (5.16g). ¹ H NMR (CDCl₃): δ 6.85 (d, J=11.8 Hz, 1 H), 6.52 (d, J=7.8 Hz, 1H), 6.0-5.85 (m, 1 H), 5.05 (m, 3 H), 5.00 (m, 1 H), 3.78 (s, 3 H). MS(EI, 70 eV): m/z (rel.int) 182 (M⁺, 84).

2-Fluoro-5-methoxy-4-propylphenol

4-Allyl-2-fluoro-5-methoxyphenol (5.16 g, 28.3 mmol) was dissolved inEtOH (150 mL) and Pd/C (5%, 250 mg) was added. Hydrogenation for 6 h atroom temperature and atmospheric pressure, addition of more Pd/C (5%,100mg), continued reaction for 3 h followed by removal of the catalyst andevaporation of the solvent gave 2-fluoro-5-methoxy-4-propylphenol (4.52g) as an oil. ¹ H NMR (DMSO-d₆): δ 9.53 (s, 1 H), 6.85 (d, J=11.8 Hz, 1H), 6.51 (d, J=7.7 Hz, 1 H), 3.67 (s, 3 H), 2.38 (t, J=7.5 Hz, 2 H),1.46 (m, J=7.5 Hz, 2 H), 0.84 (t, J =7.4 Hz, 3 H). ¹³ C MNR (DMSO-d₆):δ153.21, 144.84 (d, J=230 HZ), 142.70 (d, J=13 Hz), 120.41 (d, J=5 Hz),116.46 (d, J=19 Hz), 101.25, 55.62, 30.68, 22.61, 13.71. MS (EI, 70 eV):m/z (rel.int.) 184 (M⁺,69).

2-Fluoro-5-methoxy-4-propylphenyl triflate

2-fluoro-5-methoxy-4-propylphenol (4.52 g, 24.5 mmol) was dissolved inCH₂ Cl₂ (100 mL), triethylamine (6.84 mL, 49.1 mmol) and4-(N,N-dimethylamino)pyridine (5 mg, 0.04 mmol) was added and thesolution was cooled to -70° C. Trifluoromethanesulfonic anhydride (6.19mL, 36.8 mmol) was added dropwise during 20 min and the reaction waskept at -70° C. for another 20 min. CH₂ Cl₂ (100 mL) was added and thesolution was washed with water (50 mL) and brine (2×50 mL) followed bydrying (MgSO₄). Evaporation of the solvent gave 8.2 g of crude product.Filtration through SiO₂ (70 g) using CH₂ Cl₂ as eluent and purificationby flash chromatography (SiO₂, CH₂ Cl₂ -hexane 1:2) gave2-fluoro-5-methoxy-4-propylphenyl triflate (6.08 g) as an oil. ¹ H NMR(DMSO-d₆): δ 7.36 (d, J=11.0 Hz, 1 H), 7.21 (d, J=6.4 Hz, 1 H), 3.79 (s,3 H), 2.52 (t, J=7.7 Hz, 2 H), 1.52 (m, J=7.5 Hz, 2 H), 0.87 (t, J=7.4Hz, 3 H). ¹³ C NMR (DMSO-d₆): δ 153.62 (d, J=242 Hz), 133.63 (d, J=15Hz), 132.96 (d, J=6 Hz), 118.15 (q, J=320 Hz), 117.75 (d, J=20 Hz),106.18, 56.51, 31.00, 21.92, 13.63. MS (EI, 70 eV): m/z (rel.int) 316(M⁺, 100).

Methyl 2-fluoro-5-methoxy-4-propylbenzoate

2-Fluoro-5-methoxy-4-propylphenyl triflate (3.00 g, 9.5 mmol),triethylamine (2.91 mL, 20.9 mmol) and methanol (7.0 mL, 173 mmol) weredissolved in DMF (30 mL) and the solution was flushed with CO.1,3-Bis(diphenylphosphino)propane (151 mg, 0.37 mmol) andpalladium-acetate (84 mg, 0.37 mmol) were added and the reaction wasstirred at 70° C. and atmospheric pressure for 4.5 h. Evaporation of thesolvent and co-evaporation with xylene gave a residue which wasextracted between Et₂ O and 2M NaOH and the organic phase was washedbrine, dryed over MgSO₄ and evaporated to give 2.3 g of crude product.Purification by flash chromatography (SiO₂, CH₂ Cl₂ -hexane 1:2) gavemethyl 2-fluoro-5-methoxy-4-propylbenzoate (1.46 g) as an oil. ¹ H NMR(DMSO-d₆): δ 7.28 (d, J=6.0 Hz, 1 H), 7.12 (d, J=11.4 Hz, 1 H), 3.83 (s,3 H), 3.80 (s, 3 H), 2.54 (t, J=7.6 Hz, 2 H), 1.53 (m, J=7.6 Hz, 2 H),0.87 (t, J=7.4 Hz, 3 H). ¹³ C NMR (DMSO-d₆): δ 164.01 (d, J=4 Hz),155.21 (d, J=251 Hz), 152.95, 138.30 (d, J=8 Hz), 117.93 (d, J=24 Hz),115.26 (d, J=11 Hz), 111.75, 55.88, 52.20, 31.32, 21.83, 13.66. MS (EI,70 eV): m/z (rel.int) 226 (M⁺, 100).

2-Fluoro-5-hydroxy-4-propylbenzoic acid

Methyl 2-fluoro-5-methoxy-4-propylbenzoate (1.27 g, 5.63 mmol) wasdissolved in CH₂ Cl₂ (20 mL) and cooled to -70° C. Boron tribromide(1.64 mL, 16.9 mmol) was added and the temperature was slowly raised to0° C. during 4.5 h. Methylene chloride (20 mL) and 2M NaOH (25 mL) wereadded and the mixture was stirred over-night at room temperature. Water(20 mL) was added, the phases separated and the aqueous phase wasextracted with CH₂ Cl₂ (20 mL) and acidified to pH 1 by concentrated HClthus precipitating the acid. Ethyl acetate (50 mL) was added to themixture and the phases separated. The aqueous phase was extracted byadditional EtOAc (50 mL) and the combined organic phases were washedwith brine (20 mL), dried (MgSO₄) and evaporated yielding2-fluoro-5-hydroxy-4-propylbenzoic acid (1.09 g) Mp: 134.5°-135.5° C. ¹H NMR (DMSO-d₆): d 12.88 (br, 1 H), 9.57 (br, 1 H), 7.23 (d, J=6.5 Hz, 1H), 6.96 (d, J=11.6 Hz), 2.48 (t, J=7.5 Hz, 2 H), 1.53 (m, J=7.5 Hz, 2H), 0.87 (t, J=7.4 HZ, 3 H). ¹³ C NMR (DMSO-d₆): δ 164.96 (d, J=3 Hz),154.38 (d, J=248 Hz), 150.84 (d, J=2 Hz), 135.82 (d, J=7 Hz), 117.44 (d,J=24 Hz), 116.28 (d, J=11 Hz), 116.22, 31.38, 21.79, 13.65. MS (EI, 70eV): m/z (rel.int) 198 (M⁺, 38).

6-Fluoro-3-hydroxy-2-nitro-4-propylbenzoic acid2-Fluoro-5-hydroxy-4-propylbenzoic acid (500 mg, 2.52 mmol) wasdissolved in nitromethane (50 mL) through heating to 40° C. and nitricacid (90%, 120 μL, 2.52 mmol) was added. After 10 min at 40° C. followedby reaction at room temperature for 2 h the solvent was evaporated. Theresidue was dissolved in EtOAc (150 mL), washed with brine (10 mL),dried (MgSO₄) and concentrated to dryness giving 640 mg of crudeproduct. Subsequent purification by flash chromatography (SiO₂,EtOAc-HOAc 50:1) afforded pure6-fluoro-3-hydroxy-2-nitro-4-propylbenzoic acid (294 mg). Mp:128.0°-129.0° C. ¹ H NMR (DMSO-d₆); δ 10.2 (br, 1 H), 7.39 (d, J=10.4Hz, 1 H), 2.63 (t, J=7.6 Hz, 2 H), 1.55 (m, J=7.5 HZ, 2 H), 0.89 (t,J=7.4 Hz, 3 H). ¹³ C NMR (DMSO-d₆): δ 162.49, 151.66 (d, J=245 Hz),143.69, 138.74 (d, J=5 Hz), 138.17 (d, J=8 Hz), 120.25 (d, J=23 Hz),113.82 (d, J=21 Hz), 31.44, 21.92, 13.60. MS (EI, 70 eV): m/z (rel.int)243 (M⁺, 88).

6-Fluoro-3-hydroxy-4-propylanthranilic acid hydrochloride

6-Fluoro-3-hydroxy-2-nitro-4-propylbenzoic acid (274 mg, 1.13 mmol) wasdissolved in a mixture of dioxane (25 mL) and water (40 mL) and 5% Pd/C(25 mg) was added. Hydrogenation at room temperature and atmosphericpressure for 3 h, addition of more catalyst (10 mg), continuedhydrogenation overnight, removal of the catalyst, addition of moredioxane (10 mL) and new catalyst (30 mg) followed by reaction for 3 h,filtration and evaporation of the solvents, gave 205 mg of crudeproduct. Purification by flash chromatography (SiO₂, EtOAc-HOAc 50:1)gave 105 mg of an almost pure compound which was dissolved in THF (1.5mL) and the hydrochloride salt precipitated by addition of HCl/Et₂ O(3M, 3 ml). The salt was washed with Et₂ O (3×3 m) and aftervacuum-drying 6-fluoro-3-hydroxy-4-propylanthranilic acid hydrochloride(88 mg) was obtained. Mp: 173° C. (dec.). ¹ H NMR (DMSO-d₆): δ8.27 (br,5 H), 6.23 (d, J=12.5 Hz), 2.48 (t, J=7.6 Hz, 2 H), 1.49 (m, J=7.5 Hz, 2H), 0.86 (t, J=7.3 Hz, 3 H). ¹³ C NMR (DMSO-d₆): δ 167.40, 155.73 (d,J=246 Hz, 139.64 (d, J=4 Hz), 138.11, 133.93 (d, J=10 Hz), 103.91 (d,J=24 Hz), 100.91 (d, J=16 Hz), 31.68, 22.11, 13.82. MS (EI, 70 eV): m/e(rel.int.) 213 (M+, 59).

Example 4 (Method A) Preparation of 4,6-dichloro-3-hydroxyanthranilicacid

4,6-Dichloro-3-hydroxy-2-nitrobenzoic acid

4,6-Dichloro-3-hydroxybenzoic acid³ (280 mg, 1.35 mmol) was dissolved innitromethane (35 mL) by heating to 45° C. Nitric acid (90%, 63 RL,1.35mmol) was added and after 4 h at 45° C. the solvent was evaporated. Theresidue was partitioned between EtOAc (100 mL) and water (5 mL), theorganic phase washed with brine (5 mL), dried (MgSO₄) and evaporatedgiving 327 mg of crude product. Purification by column chromatography(SiO₂) using EtOAc-HOAc 50:1 as eluent afforded pure4,6-dichloro-3-hydroxy-2-nitrobenzoic acid (232 mg). Mp: 186° C. (dec.).¹ H NMR (DMSO-d₆): δ 7.88 (s, 1 H) ¹³ C NMR (DMSO-d₆): δ163.76, 147.25,139.03, 133.06, 128.06, 126.28, 118.23. MS (EI, 70 eV): m/z (rel.int)253/251 (M⁺, 34/49).

4,6-Dichloro-3-hydroxyanthranilic acid hydrochloride

4,6-Dichloro-3-hydroxy-2-nitrobenzoic acid (223 mg, 0.88 mmol) wasdissolved in EtOH (50 mL) and Pd/C (10%, 30 mg) was added. Hydrogenationat atmospheric pressure and at room temperature for 1 h, filtration andevaporation of the solvent gave 205 mg of crude product. Purification bycolumn chromatography (SiO₂, EtOAc-HOAc 50:1) gave a residue which wasrecrystallized from MeOH/water (0.5/ 1.5 mL). Column chromatography(SiO₂, EtOAc-HOAc 400:1) followed by dissolving the free amine in THF(0.6 mL) and precipitating the hydrochloride by adding HCl/Et₂ O (3M, 1mL) and Et₂ O (1 mL) gave 4,6-dichloro-3-hydroxyanthranilic acidhydrochloride (32 mg). Mp: 231° C. (dec.). ¹ H NMR (DMSO-d₆): δ 7.0 (br,5 H), 6.68 (s, 1 H). ¹³ C NMR (DMSO-d₆): δ 167.15, 140.27, 139.05,122.49, 121.88, 116.24, 113.99. MS (EI, 70 eV): m/z (rel.int.) 223/221(M⁺, 42/65).

Example 5 (Method A) Preparation of4-Bromo-6-fluoro-3-hydroxyanthranilic acid

6-Fluoro-3-methoxybenzoic acid

4-Fluoro-3-methylanisol (1.0 g, 7.1 mmol) was dissolved in a mixture ofpyridine (16 mL) and water (32 mL). Potassium permanganate (3.4 g, 21mmol) was added and the reaction mixture was refluxed for 3 h and thenleft at room temperature over night. After filtration and extractionwith CH₂ Cl₂ the aqueous phase was acidified with HCl precipitating theproduct (440 mg).

¹ NMR (CD₃ OD): δ7.44-7.47 (m, 1 H), 7.18-7.16 (m, 2H), 3.86 (s, 3 H);¹³ C NMR (CD₃ OD): δ 167.55, 158.35 (d, J=192 Hz), 156.30, 121.65 (d,J=8.7 Hz), 120.63 (d), 118.94 (d, J=24.4 Hz), 117.03, 56.59.

6-Fluoro-3-hydroxybenzoic acid

6-Fluoro-3-methoxybenzoic acid (500 mg, 2.94 mmol) was mixed withfreshly distilled 48% HBr (20 mL) and heated at 100° C. for 14 h. Waterand HBr were evaporated and the crude product (462 mg) was used withoutfurther purification. ¹ H NMR(CD₃ OD): δ 7.28-7.29 (m, 1H), 6.92-7.12(m, 2 H); ¹³ C NMR (CD₃ OD): δ 167.80, 157.26 (d, J=249 Hz), 154.77,122.52 (d, J=10.4 Hz), 120.49 (d, J=11 Hz), 118.77 (d, J=19 Hz), 118.58.

6-Fluoro-3-hydroxy-2-nitrobenzoic acid

6-Fluoro-3-hydroxybenzoic acid (100 mg, 0.64 mmol) was dissolved in CH₃NO₂ (10 mL) and cooled to 0° C. HNO₃ (90%, 31 μL, 0.64 mmol) was addedand the reaction was left at 0° C. for 4 h and then at room temperatureover night. Evaporation and purification by flash chromatography on SiO₂(Toluene-EtOAc-HOAc) gave the product (22 mg). ¹ H NMR (CD₃ OD): δ 7.32(t, J=9.0 Hz, 1 H), 7.15 (dd, J₁ =9.3 Hz, J₂ =4.4 Hz, 1 H); ¹³ C NMR: δ164.97, 153.68 (d, J=247 Hz), 148.78, 122.67, 122.56, 122.45, 122.13.

4-Bromo-6-fluoro-3-hydroxy-2-nitrobenzoic acid

6-Fluoro-3-hydroxy-2-nitrobenzoic acid (22 mg, 0.11 mmol) was dissolvedin acetic acid (2 mL). Sodium acetate (10 mg, 0.12 mmol) and Br₂ (10 μL,0.19 mmol) was added and the reaction mixture was left at roomtemperature for 14 h. The temperature was raised to 50 and the reactionwas continued for another 4 h. Evaporation gave a residue which wasdissolved in water, and after adjustment of the pH the aqueous phase wasextracted with EtOAc. Washing of the organic phase with water andevaporation gave a crude product which was purified by flashchromatography on SiO₂. Eluation with toluene-EtOAc-HOAc afforded theproduct (23 mg). ¹ NMR (CD₃ OD): δ 8.0 (d, J=8.7, 1 H); MS (EI, 70 eV):m/z (rel. int.) 279/281 (M⁺, 40/38)

4-Bromo-6-fluoro-3-hydroxyanthranilic acid

4-Bromo-6-fluoro-3-hydroxy-2-nitrobenzoic acid (22 mg 0.78 mmol) wasdissolved in EtOH (10 mL) and PtS₂ (2 mg) was added. Hydrogenation atroom temperature and at atmospheric pressure for 14 h followed byfiltration and evaporation gave a crude product. Purification by flashchromatography (SiO₂, toluene-EtOAc-HOAc) afforded the product (4 mg). ¹H NMR (CD₃ OD): δ 6.44 (d, J=11.3 Hz, 1 H); MS (EI, 70 eV): m/z (rel.int.) 249/251 (M⁺, 93/90).

Example 6 (Method B) Preparation of4-chloro-3-hydroxy-6-trifluoromethylanthranilic acid

1-Chloro-2-methoxy-3-nitro-5-trifluoromethylbenzene

2-Chloro-6-nitro-4-trifluoromethylphenol⁴ (5.3 g, 22 mmol) was dissolvedin acetone (120 mL). Potassium carbonate (6.1 g, 44 mmol) and dimethylsulfate (4.3 mL, 44 mmol) was added and the solution was stirred for 3 hat 80° C. The solvent was evaporated and the crude product was dissolvedin EtOAc and extracted with 2M NaOH (2) and brine (2). Drying (MgSO₄),filtration and evaporation gave a brown oil (7.9 g) Purification on asilica gel coloumn (EtOAc-toluene-HOAc 100:100:1) gave the titlecompound as a yellow oil (3.9 g). ¹ H NMR (CDCl₃): 7.99 (d, J=2.08 Hz, 1H), 7.90 (d, J=2.08 Hz, 1 H), 4.09 (s, 3 H). MS (EI, 70 eV): m/z (rel.int.) 257/255 (M⁺, 17/49).

3-Chloro-2-methoxy-5-trifluoromethylaniline

1-Chloro-2-methoxy-3-nitro-5-trifluoromethylbenzene (3.46 g, 13.5 mmol)was dissolved in MeOH (74 mL). Hydrochloric acid (2M, 13 mL, 26 mmol)and Pd/C (10%, 0.44 g) was added. Hydrogenation at atmospheric pressureand at room temperature for 1 h 30 min, filtration and evaporation ofthe solvent gave a crude product. Purification by flash chromatography(SiO₂, CH₂ Cl₂ -hexarne 1:2 followed by EtOAc-NH₃ 100:0.1) yielded thetitle compound (3.08 g) as an oil. ¹ H NMR (CDCl₃): 7.00 (J 1.8 Hz, 1H), 6.85 (d, J=1.95 Hz, 1 H), 4.11 (br s, 2 H), 3.87 (s, 3 H). MS (EI,70 eV): m/z (rel. int.) 227/225 (M⁺, 17/58).

1-Chloro-3-isonitrosoacetamido-2-methoxy-5-trifluoromethylbenzene

Chloral hydrate (334 mg, 2.02 mmol) was dissolved in H₂ O (6 mL). Amixture of 3-chloro-2-methoxy-5-trifluoromethylaniline (350 mg, 1.55mmol) in DMF (2 mL), H₂ O (2 mL) and HCl (12M, 0.14 mL, 1.7 mmol) wasadded. The reaction mixture was stirred at 95° C. for 15 min.Hydroxylamine hydrochloride (431 mg, 6.21 mmol) was added and thestirring at 95° C. for 2 h 40 min was continued. Evaporation andco-evaporation with xylene gave a residue which was extracted betweenEtOAc and H₂ O. The H₂ O phase was neutralized to pH 7 with NaHCO₃ (aq,sat) and then washed with EtOAc (2). The combined organic phases weredried (Na₂ SO₄), filtered and evaporated. Purification of the crudeproduct (448 mg) by flash chromatography (SiO₂, gradient EtOAc-hexane1:20 1:4) yielded the title compound (146 mg) as a white powder. ¹ H NMR(CD₃ OD): 8.57 (d, J=1.96 Hz, 1 H), 7.57 (s, 1 H), 7.46 (d, 1 H), 3.94(s, 3 H). MS (EI, 70 eV): m/z (rel. int.) 298/296 (M⁺, 18/61).

6-Chloro-7-methoxy-4-trifluoromethylisatin

1-Chloro-3-isonitrosoacetamido-2-methoxy-5-trifluoromethylbenzene (188mg, 0.63 mmol) was dissolved in H₂ SO₄ (conc., 4 mL) and stirred at 83°C. for 1 h 15 min. The reaction mixture was poured into ice-water (75mL). Extraction with EtOAc (250 mL), drying (Na₂ SO₄), filtration andevaporation gave a crude product (220 mg). Purification by flashchromatography (SiO₂, gradient EtOAc-hexane 1:4 4:1) yielded the yellowtitle compound (13 mg) as a tautomeric mixture according to NMR. ¹ H NMR(CD₃ OD): 7.41 and 7.35 (2 s, 1 H), 3.95 and 3.90 (2 s, 3 H). MS (EI, 70eV): m/z (rel. int.) 281/279 (M⁺, 24/77).

4-Chloro-3-methoxy-6-trifluoromethylanthranilic acid

6-Chloro-7-methoxy-4-trifluoromethylisatin (13 mg, 0.046 mmol) wasdissolved in NaOH (0.68M, 0.20 mL, 0.13 mmol) and H₂ O (0.20 mL) andthen cooled to +7° C. Hydrogen peroxide (30%, 14 L, 0.14 mmol) dissolvedin NaOH (0.68M, 0.49 mL, 0.33 mmol) was added dropwise during 1 min. Thereaction mixture was stirred for 1 h 15 min at room temperature.Additional H₂ O₂ (10 L) was added at 7° C. and then stirring wascontinued at room temperature for 2 h. Acetic acid (54 L, 0.94 mmol) wasadded, but no precipitation occured. Ethyl acetate (2 mL) was added andpH was raised to 6 with NaHCO₃ (aq, sat.). The water phase was washedwith EtOAc (3) and the combined organic layers were evaporated andco-evaporated with toluene (2). Purification by flash chromatography(SiO₂, gradient EtOAc EtOAc-HOAc 100:1) yielded the title compound (5mg). ¹ H NMR (CD₃ OD): 6.98 (s, 1 H), 3.87 (s, 3 H). MS (EI, 70 eV): m/z(rel. int.) 271/269 (M⁺, 17/48).

4-Chloro-3-hydroxy-6-trifluoromethylanthranilic acid

4-Chloro-3-methoxy-6-trifluoromethylanthranilic acid (5 mg, 0.019 mmol)was dissolved in diethyl ether (1 mL) and HCl (2M, 20 L) was added. Thesolution was evaporated and co-evaporated with toluene. The residue wasdissolved in CH₂ Cl₂ (2 mL), cooled to -60° C., and BBr₃ (9 L, 0.092mmol) was added followed by stirring at -60° C. for 3 min, 0° C. for 3 hand room temperature for 6 h. Additional BBr₃ (4 L, 0.04 mmol) was addedat -35° C. and the stirring was continued at room temperature for 2 h.The reaction mixture was cooled to -20 ° C. and added to ice-cold NaHCO₃(2 mL, sat.) followed by stirring for 1 h at room temperature. Methylenechloride (2 mL) was added and pH was adjusted to 5. The phases wereseparated and the H₂ O phase was washed with EtOAc (3). The combinedorganic layers were dried (Na₂ SO₄), filtered and evaporated. The crudeproduct was purified on a silica gel coloumn (EtOAc EtOAc-HOAc 100:1)and the title compound was isolated (3 mg). ¹ H NMR (CD₃ OD): 6.97 (s, 1H). MS (EI, 70 eV): m/z (rel. int.) 257/255 (M⁺, 0.16/0.54)

Example 7 (Method E) Preparation of4,6-Dibromo-N-4-(2,4-dimethoxyphenyl)butyl-3-hydroxyanthranilic acid

1-(4-bromobutyl)-2,4-dimethoxybenzene

Commercially available copper(I)bromide (7.17 g, 50 mmol) and anhydrouslithium bromide (8.68 g, 100 mmol) were added to anhydrous THF (100 mL).Vigorous shaking gave a dark greenish solution. 11.5 mL (5.75 mmol) ofthis solution was added to a mixture of 1,4-dibromobutane (74.8 g, 346mmol) in THF (90 mL). The mixture was warmed to 40°C, after which asolution of 2,4-dimethoxyphenylmagnesium bromide (115 mmol) in THF (100mL), prepared by standard methods, was added over 45 min. Thetemperature was never more than 50° C. After the addition, the mixturewas stirred for an additional 1 h at 50° C. The reaction mixture wasallowed to reach 30° C. after which it was poured into ice water (200mL). Effective stirring for 10 min gave a deep blue color. The mixturewas extracted with diethyl ether (2×250 mL), dried (MgSO₄) andevaporated. The excess of 1,4-dibromobutane was distilled off, and theresidue was filtered through a short column of silica gel (hexane-EtOAC,95:5). Evaporation gave the title compound as a colorless liquid (23.0g): ¹ H NMR (CDCl₃ -d) 7.00 (d, J=8.0 Hz, 1 H), 6.44-6.39 (m, 2 H), 3.79(s, 6 H), 3.42 (t, J=6.9 Hz, 2 H), 2.56 (t, J=7.5 Hz, 2 H), 1.90-1.83(m, 2 H), 1.73-1.62 (m, 2 H); ¹³ C NMR (CDCl₃ -d) 159.13, 158.24,129.90, 122.56, 103.74, 98.44, 55.30, 55.22, 33.87, 32.47, 28.56 (twooverlapping carbon); MS (EI, 70 eV): m/z (rel.int.) 274/272 (M⁺,100/96), 151 (54), 121 (43), 91 (14).

4-(2,4-dimethoxyphenyl)butyraldehyde

A mixture of 1-(4-bromobutyl)-2,4-dimethoxybenzene (11.0 g, 40.2 mmol),sodium hydrogen carbonate (6.75 g, 80.3 mmol) and sodium iodide (9.03 g,60.2 mmol) in DMSO (80 mL) was stirred at 105° C. for 1.5 h. Thereaction mixture was allowed to cool to some extent after which icewater (240 mL) was added. The mixture was extracted with diethyl ether(2×200 mL), washed with brine (50 mL), dried (MgSO₄) and concentrated invacuo. The residue was purified by column chromatography (SiO₂,hexane-EtOAc, 80:20) yielding the title compound as a colorless liquid(3.56 g): ¹ H NMR (CDCl₃ -d) 9.74 (t, J=1.8 Hz, 1 H), 7.00 (d, J=7.9 Hz,1 H), 6.45-6.40 (m, 2 H), 3.79 (s, 3 H), 3.79 (s, 3 H), 2.59 (t, J=7.4Hz, 2 H), 2.44-2.39 (m, 2 H), 1.90 (quintet, J=7.4 Hz, 2 H); ¹³ C NMR(CDCl₃ -d) 202.91, 159.32, 158.28, 130.14, 121.90, 103.78, 98.44, 55.28,55.16, 43.25, 28.80, 22.50; MS (EI, 70 eV): m/z (rel.int.) 208 (M⁺, 31),164 (44), 151 (100), 121 (76), 91 (16).

4,6-Dibromo-N-4-(2,4-dimethoxyphenyl)butyl-3-hydroxyanthranilic acid

A solution of 4-(2,4-dimethoxyphenyl)butyraldehyde (62 mg, 0.30 mmol) indry methanol (2 mL) was added to a mixture of4,6-dibromo-3-hydroxyanthranilic acid (93 mg, 0.30 mmol) and Na₂ SO₄(128 mg, 0.90 mmol) in methanol (10 mL). The reaction mixture wasstirred for 3 h at room temperature. Sodium cyanoborohydride (30 mg,0.48 mmol) was added, and the mixture was stirred for a further 2 h.Conc. acetic acid (1 mL) was added, and the solvent was evaporated. Theresidue was partitioned between EtOAc (40 mL) and water (5 mL). Thelayers were separated, and the aqueous layer was saturated with NaCl (s)and extracted with EtOAc (2×20 mL). The combined organic layers weredried (MgSO₄) and evaporated. Recrystallization from EtOAc yielded 24 mgof crystalline product. The mother liquor was purified by columnchromatography (SiO₂, EtOAc-hexane-conc. HOAc 60:40:1) which gaveanother 17 mg of product. The combined material was recrystallized fromEtOAc-hexane 60:40 (14 mL). The title compound was obtained as whitecrystals (28 mg). Mp decomposes >150°C.; ¹ H NMR (DMSO-d₆) 7.06 (s, 1H), 6.97 (d, J=8.2 Hz, 1 H), 6.48 (d, J=2.3 Hz, 1 H), 6.40 (dd, J=8.2Hz, 2.3 Hz, 1 H), 3.73 (s, 1 H), 3.71 (s, 3 H), 3.08 (m, 2 H), 2.43 (m,2 H), 1.46 (m, 4 H); ¹³ C NMR (DMSO-d₆) 168.29, 158.72, 157.78, 142.66,138.29, 129.68, 122.93 (two overlapping carbon), 121.91, 111.38, 109.64,104.26, 98.27, 55.20, 55.01, 44.93, 29.48, 28.53, 26.76; MS (EI, 70 eV):m/z (rel.int.) 505/503/501 (M⁺, 1/2/1), 461/459/457 (21/42/23),281/279/277 (26/54/32). Anal.Calcd for C₁₉ H₂₁ Br₂ NO₅ : C, 45.4; H,4.2; N, 2.8. Found: C, 45.0; H, 4.1; N, 2.6.

Example 8 (Method E) Preparation of4,6-Dibromo-3-hydroxy-N-(2-thienyl)-methylanthranilic acid

4,6-Dibromo-3-hydroxy-N-(2-thienyl)methylanthranilic acid

A solution of 2-thiophenecarboxaldehyde (38 mg, 0.34 mmol) in drymethanol (0.8 mL) was added to a mixture of4,6-dibromo-3-hydroxyanthranilic acid (105 mg, 0.34 mmol) and Na₂ SO₄(240 mg, 1.7 mmol) in methanol (2 mL ). The reaction mixture was stirredovernight at room temperature. Sodium cyanoborohydride (32 mg, 0.51mmol) was added, and the mixture was stirred for 2 days at roomtemperature. Conc. acetic acid (1 mL) was added, and the solvent wasremoved in vacuo. The residue was partitioned between brine and EtOAc(20 mL). The layers were separated and the aqueous layer was extractedwith EtOAc (20 mL). The combined organic layers were dried (MgSO₄) andconcentrated under reduced pressure. The obtained material was purifiedby column chromatography (SiO₂, CH₂ Cl₂ -hexane-EtOAc-conc. HOAc30:30:20:3). Preparative HPLC (H₂ O-acetonitrile-conc. HOAc 50:50:1)yielded the title compound as a yellowish solid (17 mg): ¹ H NMR (CD₃OD-d₄) 7.26 (dd, J=5 Hz, 1 Hz), 7.20 (s 1 H), 6.99 (m, 1 H), 6.92 (dd,J=5 Hz, J=5 Hz, 1 H), 4.54 (s, 2 H); MS (TSP): m/z (rel.int.)410/408/406 (M+1, 5/12/7), 234/232 (31/28), 154 (100).

References

1. Ellis R. C., Whalky W. B, Ball K. J Chem Soc, Perkin Trans 1 (13)1377-82 (Eng), 1976

2. Sinhababu A. K., Kawase M., Borchardt R. T. Tetrahedron Lett. 28 (36)4139-42, 1987

3. Chen A. Eur. Pat. Appl. EP 108526 A2 16 May 1984

4. Marhold A., Klauke E., Ger. Offen. DE 2733682 , 8 Feb. 1979

Pharmacological method

Materials

Carboxy-¹⁴ C!3-hydroxyanthranilic acid (6 mCi/mmol) was received fromDrs. E. Shaskan and L. Spitznagle (University of Connecticut,Farmington, Conn., U.S.A.). ³ H!QUIN was obtained from the NuclearResearch Center (Negev, Israel). All other chemicals and reagents wereobtained from commercial suppliers.

Tissue preparations

For routine assays, male Sprague-Dawley rats (150-200 g) were killed bydecapitation and their brains rapidly dissected onto ice. Wholeforebrains or individual CNS regions were sonicated in four volumes(wt/vol) of distilled water, centrifuged at 50,000 g for 20 min at 4°C., and the resulting supernatant used for the assay. For subcellularfractionation, the method of Mena et al. (1980) was used and thefollowing fractions were collected: P1 (nuclear fraction), P2 (crudesynoptosomal fraction), P3 (microsomal fraction), soluble (cytosolfraction), myelin, synaptosomes, and mitochondria. All nonsolublefractions were sonicated prior to assay.

Measurement of 3-HAO activity

For routine assays, 20 μl of tissue extract (equivalent to 5 mg oforiginal tissue wet weight) were incubated in the presence or absence ofinhibitor (in 10 μl) at 37° C. for 30 min in a solution containing 0.3mM Fe (SO4)2, 38 mM 4-(2-hydroxyethyl)piperazine-1-ethanesulfonic acid(HEPES)/NaOH buffer (pH 6.0), and 5 μM ( 14C!3HANA in a total volume of195 μl. Blank values were obtained under identical conditions usingtissue that had been heated for 5 min in a boiling water bath. Theincubation was terminated by the addition of 50 μl 6% HClO₄, the tubescooled on ice, and the precipitate removed by a 2-min centrifugation ina Beckman microfuge. 220 μl of supernatant were applied to a Dowex 50 W(200-400 mesh) cation-exchange column (0.5×2 cm), which was washed with1 ml of distilled H2O to collect the ¹⁴ C! QUIN produced. 5.5 ml ofscintillation fluid were added to the eluate and its radioactivitydetermined by liquid scintillation spectrometry. Preliminary experimentshad indicated that 90-95% of ¹⁴ C!QUIN was collected by this procedure,whereas unreacted ¹⁴ C!3HANA remained on the column.

Pharmaceutical formulations

The administration in the novel method of treatment of this inventionmay conveniently be oral, rectal, or parenteral at a dosage level of,for example, about 1 to 3000 mg/kg, preferably about 10 to 1000 mg/kgand especially about 25 to 250 mg/kg and may be administered on aregimen of 1 to 4 hours per day. The dose will depend on the route ofadministration, a particularly preferred route being by intravenousinfusion of an aqueous solution containing a compound according toformula I. It will be appreciated that the severity of the disease, theage of the patient and other factors normally considered by theattending physician will influence the individual regimen and dosagemost appropriate for a particular patient.

The pharmaceutical formulations comprising the compound of thisinvention may conveniently be tablets, pills, capsules, syrups, powdersor granules for oral administration; sterile parenteral solutions orsuspensions for parenteral administration; or as is suppositories forrectal administration.

To produce pharmaceutical formulations containing a compound accordingto the present invention in the form of dosage units for oralapplication, e.g. lactose, saccharose, sorbitol, mannitol, starches suchas potato starch, corn starch or amylopectin, cellulose derivatives, abinder such as gelatine or polyvinylpyrrolidone, and a lubricant such asmagnesium stearate, calcium stearate, polyethylene glycol, waxes,paraffin, and the like, and then compressed into tablets. If coatedtablets are required, the cores, prepared as described above, may becoated e.g. gum arabic, gelatine, talcum, titanium dioxide, and thelike. Alternatively, the tablet can be coated with a polymer known tothe person skilled in the art, dissolved in a readily volatile organicsolvent or mixture of organic solvents. Dyestuffs may be added to thesecoatings in order to readily distinguish between tablets containingdifferent active substances or different amounts of the activecompounds.

For the preparation of soft gelatine capsules, the active substance maybe admixed with e.g. a vegetable oil or polyethylene glycol. Hardgelatine capsules may contain granules of the active substance usingeither the above-mentioned excipients for tablets e.g. lactose,saccharose, sorbitol, mannitol, starches (e.g. potato starch, cornstarch or amylopectin), cellulose derivatives or gelatine. Also liquidsor semisolids of the drug can be filled into hard gelatine capsules.

Dosage units for rectal application can be solutions or suspensions orcan be prepared in the form of suppositories comprising the activesubstance in admixture with a neutral fatty base, or gelatine rectalcapsules comprising the active substance in admixture with vegetable oilor paraffin oil.

Liquid preparations for oral application may be in the form of syrups orsuspensions, for example solutions containing from 0.2% to about 20% byweight of the active substance herein described, the balance being sugarand mixture of ethanol, water, glycerol and propylene glycol. Optionallysuch liquid preparations may contain colouring agents, flavouringagents, saccharine and carboxymethylcellulose as a thickening agent orother excipients known to the person skilled in the art.

Solutions for parenteral applications by injection can be prepared in anaqueous solution of a water-soluble pharmaceutically acceptable salt ofthe active substance, preferably in a concentration of from about 0.5%to about 10% by weight. These solutions may also contain stabilizingagents and/or buffering agents and may conveniently be provided invarious dosage unit ampoules.

We claim:
 1. A compound of the general formula I ##STR42## wherein R¹and R² are the same or different and selected from H, alkyl, aryl andarylalkyl; X and Y are the same or different and selected from alkoxy,aryloxy, alkyl, alkylthio, arylthio, fluoroalkyl, halogen, cyano, OSO₂CH₃, OSO₂ CF₃, OCF₃ and SCF₃ with the proviso that the compound offormula I wherein R¹ and R² =H, X=Br and Y=CH₃ is excluded; or apharmaceutically acceptable salt thereof.
 2. A compound according toclaim 1 wherein alkyl when R¹, R², X and/or Y represent alkyl; R¹ and/orR² represent arylalkyl; or when X and/or Y represent an alkoxy,alkylthio or fluoralkyl is a straight or branched lower alkyl,preferably a C_(-C) ₆ alkyl.
 3. A compound according to claim 1 whereinX and/or Y representing a halogen is selected from iodo, fluoro, chloroand bromo.
 4. A compound according to claim 1 wherein aryl when R¹and/or R² represent aryl or arylalkyl; X and/or Y represent aryloxy orarylthio is a phenyl, furyl or thienyl group in which the ring isoptionally further substituted by lower alkyl, lower alkoxy or halogen.5. A process for the preparation of a compound of formula I according toclaim 1 by which comprisesA) in the case where R¹ and R² =H; X and Y arethe same or different and selected from the group consisting of alkoxy,aryloxy, alkyl, alkylthio, arylthio, fluoroalkyl, halogen, cyano, OSO₂CH₃, OSO₂ CF₃, OCF₃ and SCF₃ reducing a compound of formula II ##STR43##wherein X and Y are as defined in A) above; B) in the case where R¹ andR² are the same or different and selected from the group consisting ofH, alkyl, aryl and arylalkyl; X and Y are the same or different andselected from the group consisting of alkoxy, aryloxy, alkyl, alkylthio,arylthio, fluoroalkyl, halogen, cyano, OSO₂ CH₃, OSO₂ CF₃, OCF₃ andSCF_(3k) deprotecting a compound of formula III ##STR44## wherein R¹,R², X and Y are as defined in B) above and PG is a protecting groupselected from the group consisting of alkyl, benzyl (Bn),2-(trimethylsilyl)ethoxymethyl (SEM), methoxymethyl (MOM) and2-methoxyethoxymethyl (MEM) ; C) in the case where R¹ and R² are thesame or different and selected from the group consisting of H, alkyl,aryl and arylalkyl; X and Y are the same or different and selected fromthe group consisting of alkoxy, aryloxy, alkyl, alkylthio, arylthio,fluoroalkyl, halogen, cyano, OSO₂ CH₃, OSO₂ CF₃, OCF₃ and SCF₃deesterifying a compound of formula IV ##STR45## wherein R¹, R², X and Yare as defined in C) above and R³ is selected from the group consistingof alkyl, Bn, SEM, MEM, MOM and 2,2,2-trichloroethyl; D) in the casewhere R¹ and R² are the same or different and selected from the groupconsisting of H, alkyl, aryl and arylalkyl; X and Y are the same ordifferent and selected from the group consisting of alkoxy, aryloxy,alkyl, alkylthio, arylthio, fluoroalkyl, halogen, cyano, OSO₂ CH₃, OSO₂CF₃, OCF₃ and SCF₃ deesterifying and deprotecting a compound of formulaV ##STR46## wherein R¹, R², X and Y are as defined in D) above and R³and PG are selected from the group consisting of alkyl, Bn, SEM, MEM andMOM; or E) in the case where R¹ alkyl, aryl or arylalkyl; R² =H, alkyl,aryl or arylalkyl; X and Y are the same or different and selected fromthe group consisting of alkoxy, aryloxy, alkyl, alkylthio, arylthio,fluoroalkyl, halogen, cyano, OSO₂ CH₃, OSO₂ CF₃, OCF₃ and SCF₃alkylating a compound of formula VI ##STR47## wherein X and Y are asdefined in E) above.
 6. A pharmaceutical formulation containing acompound of the general formula I ##STR48## wherein R¹ and R² are thesame or different and selected from H, alkyl, aryl and arylalkyl;X and Yare the same or different and selected from alkoxy, aryloxy, alkyl,alkylthio, arylthio, fluoroalkyl, halogen, cyano, OSO₂ CH₃, OSO₂ CF₃,OCF₃ and SCF₃ ;as active ingredient and a pharmaceutically acceptablecarrier.
 7. A method for the prevention or treatment ofneurodegeneration which comprises administering to a host in need ofsuch a treatment a sufficient amount of a compound of formula I##STR49## or a pharmaceutically acceptable salt thereof wherein R¹ andR² are the same or different and selected from H, alkyl, aryl andarylalkyl; X and Y are the same or different and selected from alkoxy,aryloxy, alkyl, alkylthio, arylthio, fluoroalkyl, halogen, cyano, OSO₂CH₃, OSO₂ CF₃, OCF₃ and SCF₃.
 8. A compound of the general formula III##STR50## wherein R¹ and R² are the same or different and selected fromH, alkyl, aryl and arylalkyl; X and Y are the same or different andselected from alkoxy, aryloxy, alkyl, alkylthio, arylthio, fluoroalkyl,halogen, cyano, OSO₂ CH₃, OSO₂ CF₃, OCF₃ and SCF₃ and PG is a protectinggroup selected from the group consisting of alkyl, Bn, SEM, MEM or MOMwith the two provisos that compounds of formula III wherein R¹ and R²=H, X=OCH₃, Y=Br, Cl or OCH₃ and PG=CH₃, and wherein R¹ and R² =H, X andY=CH₃ and PG=CH₃ are excluded.
 9. A compound of the general formula IV##STR51## wherein R¹ and R² are the same or different and selected fromH, alkyl, aryl and arylalkyl; X and Y are the same or different andselected from alkoxy, aryloxy, alkyl, alkylthio, arylthio, fluoroalkyl,halogen, cyano, OSO₂ CH₃, OSO₂ CF₃, OCF₃ and SCF₃ ; and R³ is selectedfrom alkyl, Bn, SEM, MEM, MOM and 2,2,2-trichloroethyl.
 10. A compoundof the general formula V ##STR52## wherein R¹ and R² are the same ordifferent and. selected from H, alkyl, aryl and arylalkyl; X and Y arethe same or different and selected from alkoxy, aryloxy, alkyl,alkylthio, arylthio, fluoroalkyl, halogen, cyano, OSO₂ CH₃, OSO₂ CF₃,OCF₃ and SCF₃ ; R³ and PG are selected from alkyl, Bn, SEM, MEM and MOMwith the proviso that compound.of formula V wherein R¹ and R² =H,X=OCH₃, Y=Cl, PG and R³ =CH₃ is excluded.
 11. A compound of the generalformula VI ##STR53## wherein X and Y are the same or different andselected from alkoxy, aryloxy, alkyl, alkylthio, arylthio, fluoroalkyl,halogen, cyano, OSO₂ CH₃, OSO₂ CF₃, OCF₃ and SCF₃ with the proviso thatcompound of formula VI wherein X=Br and Y=CH₃ is excluded.